This invention relates to the production of fibers of alternating aliphatic polyketones.
Polymers of carbon monoxide and ethylenically unsaturated hydrocarbons commonly referred to as aliphatic alternating polyketones (hereafter, "polyketones") are now well known. High molecular weight alternating aliphatic polyketones are of considerable interest because they exhibit a good overall set of physical and chemical properties. This class of polymers is disclosed in numerous U.S. patents assigned to Shell Oil Company exemplified by U.S. Pat. No. 4,880,903 and 4,880,904 which are incorporated herein by reference. Fibers made from polyketones can exhibit excellent properties such as tenacity, dimensional stability, hydrolytic stability, and resistance to abrasive wear.
A process for preparing fibers from polyketones is described in U.S. Pat. No. 5,045,258 which is incorporated herein by reference. This process employs hexaflouroisopropanol (HFIPA), m-cresol, and mixtures thereof as solvents for the polyketones. Until the present, these were the only materials known to be useful as solvents for polyketones. Solvents such as these present handling difficulties among other problems. U.S. Pat. No. 5,194,210 proposes solution spinning of polyketone fibers. The patent proposes that a number of organic compounds can be used to dissolve the polymer. A mixture of such solvents is said to be useful in this process. The mixture includes solvents such as ethylene carbonate or propylene carbonate and an aromatic alcohol fee of alkyl radical substituents such as resorcinol, phenol, and hydroquinone.
It has now been found that certain concentrated zinc and lithium-based preparations completely dissolve polyketones at room temperature without significantly altering the polymer backbone. These zinc and lithium-based materials can be used as solvents for producing polyketone fibers. This considerably expands the range of methods for preparing polyketone fibers.